Patent Number: 6,253,596

Title: Process and device for producing pipes as per the UOE process

Abstract: The invention relates to a process for producing pipes, especially large pipes, according to the UOE process, wherein a pipe, after internal and external seam welding, is incrementally calibrated by cold expansion up to half the pipe length. The cold expansion is simultaneously used for straightening. For this purpose, the pipe is clamped at the shortest possible distance in front of an expander head, the free pipe end is flexibly deformed, and the pipe is then cold expanded in a known manner. The prestress force thereby decreases and then, after the release of the clamping and the remaining prestress, the pipe moves incrementally by the amount of and expander step width, up to one half of the pipe length. The process is then repeated for the second half of the pipe.

Inventors: Gross-Weege; Johannes (Krefeld, DE), Ramdohr; Detlef (Krefeld, DE)

Assignee: Mannesmann AG

International Classification: B21C 37/08 (20060101); B21C 37/30 (20060101); B21C 37/06 (20060101); B21D 039/20 ()

Expiration Date: 07/03/2018